Kinetics of reactions in aqueous solutions
Rate constants for chemical reactions in various aqueous systems have been measured and analysed. A major part of this thesis discusses the effect of added salts on the reaction kinetics of organic substrates and the effect of added cosolvent on iron(II) complexes in solution. The thesis discusses the properties of aqueous solutions with reference to the prediction of trends in kinetic parameters. Transfer chemical potentials for single ions in 'urea + water' mixtures have been estimated, using solubility data for salts in conjunction with the tetraphenylarsonium tetraphenylboronate assumption. Solvent effects on the initial and transition states for reactions between iron (II) 1,10-phenanthroline and iron(II) glyoxal bis-N methylamine with hydroxide ions are also reported. Solvent effects on initial and transition states for reaction between three iron (II) complexes and hydroxide ions in 'methanol + water' mixtures are reported. Effects of added salt on the neutral hydrolysis of phenyldichloroacetate and the para-methoxy derivative are discussed in terms of solvent cosphere interactions between ions. With regard to computer-based studies osmotic coefficients for ammonium, alkylammonium and azoniaspiroalkane halides have been used with Pitzer's equations and the ideas of Wood et al to produce pairwise Gibbs function cosphere-cosphere interaction parameters. The effects of added salt on rate constants for the alkaline hydrolysis of the sodium salt of bromophenol blue are reported and analysed using Pitzer's equation for the activity coefficients of single ions in aqueous salt solutions. Internal pressures of water and deuterium oxide in the region 273.15? T/K ?373.15 and 0? P/bar ?1000 have been calculated and fitted to an equation based on a Taylor expansion about internal pressure ?i (?,0) at temperature T = 0 and pressure p = n. Calculations are reported which shed light on the controversy concerning the isobaric heat capacities for activation for the solvolysis of alkyl halides in water.